The present invention relates to a swash plate type compressor, particularly to an intake system thereof.
In general, a swash plate type compressor has a construction wherein a swash plate is fixed to a drive shaft which penetrates the axial portion of a cylinder block, so as to be inclined with the drive shaft, and pistons are slidably inserted within cylinder bores and engaged with the swash plate through bearing means.
Due to the rotation of the drive shaft, the swash plate is rotated therewith and the pistons reciprocate within the cylinder bores.
FIG. 1 is a longitudinal sectional view of the conventional swash plate type compressor having the above described construction. In FIG. 1, a front cylinder block 1 and a rear cylinder block 2 are joined so as to be opposed to each other. Both ends of the joined cylinder blocks 1 and 2 are covered by a front housing 5 and a rear housing 6 airtightly through a valve plates 3 and 4, respectively.
A drive shaft 7 extends penetrating the axial portion of the cylinder blocks 1 and 2. And a swash plate 9 is integrally fixed to the drive shaft 7 within a swash plate chamber 8 which is provided near the joining portion of the cylinder blocks 1 and 2.
Pistons 12 are engaged with the swash plate 9 through a bearing means composed of balls 10 and shoes 11. Due to the rotation of the drive shaft 7, the swash plate 9 is rotated therewith and the pistons 12 reciprocate within the cylinder bores 13 and 14 formed in the cylinder blocks 1 and 2.
As a result, the fluid flowed from suction chambers 15 formed in the front and rear housings 5 and 6 into the cylinder bores 13 and 14 is compressed and then the compressed fluid is flowed into exhaust chambers 16 formed in the front and rear housings 5 and 6. Then, the compressed fluid is supplied to an outer pipeline.
Suction passages 17F and 17R are formed between the adjacent cylinder bores. The swash plate chamber 8 is communicated with the suction chambers 15 through the suction passages 17F and 17R.
And an inlet port 18 is perforated in the outer wall of the cylinder block 2 so as to open into the nearly middle portion of the swash plate chamber 8 in a longitudinal direction thereof. The swash plate chamber 8 is communicated with an outer pipeline through the inlet port 18 and an inlet flange 19.
The fluid is sucked from the outer pipeline into the swash plate chamber 8 through the inlet flange 19 and the inlet port 18 and is introduced into the suction chambers 15 through the suction passages 17F and 17R.
In the conventional compressor having the above described construction, the inlet port 18 opens into the axially middle portion of the swash plate chamber 8, namely in the axially middle portion of the travelling range of the swash plate 9.
As shown in FIG. 1, when the swash plate 9 is inclined to the utmost limit thereof in a predetermined longitudinal section including the inlet port 18 so that one surface of the swash plate 9 facing the front housing 5 is opposed to the opening of the inlet port 18, the fluid which is introduced through the inlet port 18 toward the suction passage 17R is firstly flowed down along the surface of the swash plate 9 to the nearly central portion of the swash plate chamber 8 due to inertia thereof. Then, the fluid is flowed into the suction passage 17R over the peripheral side surface of the swash plate 9 as shown by an arrow B. As a result, the inlet resistance of the fluid flowed into the cylinder bore 14 becomes relatively larger.
In contrast, the fluid which is introduced through the inlet port 18 toward the suction passage 17F is flowed directly into the suction passage 17F as shown by an arrow A without obstructed by the swash plate 9.
Next, when the swash plate 9 is inclined into the front side of the compressor to the utmost limit in the longitudinal section as shown in FIG. 1, so that the other surface of the swash plate 9 in the rear side is opposed to the opening of the inlet port 18, the inlet resistance of the fluid flowed into the cylinder bore 13 becomes relatively larger.
As a result, it becomes difficult to make the volume of the fluid flowed into the cylinder bores of the front side and the rear side uniform constantly.
Consequently, volumetric efficiency is lowered. And the pulsation of the inlet pressure and the outlet pressure becomes larger so that the vibrations and the noize generating in the conventional compressor during its operation, become larger.
Accordingly, one object of the present invention is to provide an improved swash plate type compressor, of which volumetric efficiency is maintained good.
Another object of the present invention is to provide an improved swash plate type compressor, of which inlet resistance is scarcely obstructed by the rotation of the swash plate.
Still another object of the present invention is to provide an improved swash plate type compressor which compresses the fluid without generating vibrations or noize.